Cintec – Blastec

Reinforcement of Masonry Structures To Reduce the Risk of Progressive Collapse

Strengthening for out of plane loads

Masonry is generally designed to resist vertical loads (in-plane). However it is unable to resist out-of-plane loads to the same degree without some form of reinforcement. Such loads include high wind and hurricanes, seismic events, vehicle impacts and blast waves. Cintec is able to retro-reinforce any type of masonry wall with a matrix of steel reinforcement creating an internal skeleton capable of resisting out-of-plane loads.

Recent test evidence has shown that masonry walls that have high levels of vertical stress are more resistant to the effects of spalling following an explosive event. Using the Blastec System it is possible to artificially increase the level of vertical stress in the walls of low-level masonry structures by post-tensioning the anchors. Using this technique, these vulnerable facilities can be made to behave in a similar way to multi-storey structures offering a correspondingly higher level of protection. The post-tensioned anchors are installed vertically connecting the eaves to the foundations. They are then post-tensioned before being grouted up creating the necessary level of vertical stress.

How it works

This reinforcement, known as the “Cintec Anchor”, consists of stainless steel reinforcing bars located in diamond-drilled holes. A specially woven fabric sock surrounds each bar and is pumped full of a proprietary cementitious grout. The sock constrains the grout to remain in contact with the steel bar expanding to fill the hole creating a chemical and mechanical key in the masonry substrate. The size of the hole is chosen to ensure that the stresses at the outside of the grout are within the allowable limits of the masonry substrate. The anchors, which extend throughout the structure, are installed within the plane of the masonry walls increasing ductility and flexibility to otherwise brittle components. Once installed, the anchors are invisible to external view and can be installed without the need to remove internal or external finishes preserving architectural, historical and commercial details.